The effective response to a medical crisis requires the participation and cooperation of many entities including emergency medical services, police and fire departments, hospitals, labs, and public health among others. To this day information discovery and sharing is a challenge because of stove-pipe IT systems and organizational structures that impede it. Our goal for this Phase II project is to develop an operational prototype of a Medical Emergency Disaster Response Network (MEDRN) that provides public health, first responders and crisis managers i) secure access to distributed sources of information (e.g logistic, hospital, lab, etc.), ii) a means to collaborate by sharing information horizontally, and iii) a mechanism to gain a global common operating picture across organizations andjurisdictions. MEDRN is based on the semantic distributed network technology developed by Semandex and successfully deployed by the Department of Defense. During Phase I we proved the feasibility of the technology to implement the MEDRN; for Phase II we plan to provide the mechanisms for large scale information sharing among first responder groups and public health. To that effect we plan to a) build a minimum common ontology (MCO) for medical disaster response that borrows from emergency response and public health terminologies to define the minimum set of concepts that are required to integrate heterogeneous information systems across those communities. In effect the MCO will provide the mediation language that allows a problem that requires NxN integration points to demand only N. In addition, we plan to b) incorporate public health and emergency response messaging standards such as CAP, HL7, PHIN-MS, LOINC, etc. to interconnect with existing health and bio- surveillence system, and c) to add a minimum set of privacy and security features that satisfy HIPAA standards for the transmission of protected health data. Finally, we will d) evaluate MEDRN by conducting a live trial in a community that connects their operational systems across functions. The long-term goal of this work is to implement an "information mutual aid network" for disaster response: user communities share their information and benefit from the information of others. Semandex profits by providing access and managing MEDRN for a fee. MEDRN's technology can help public health not only with crisis management and bio- surveillance, but also with implementing the National Healthcare Information Infrastructure.